Phillip Hughes, the Australia Test batsman hit on the head by a ball two days ago, has died.
Cricket Australia chief executive officer James Sutherland has described the death as a "real-life tragedy".
The batsman, who would have been 26 on Sunday, died two days after being struck on the head by a bouncer while batting for South Australia against New South Wales at the Sydney Cricket Ground.
Sutherland said: "The word tragedy gets used far too often in sport but this freak accident is now a real-life tragedy.
"It's an understatement to say that we are completely devastated. Our grief runs deep and the impact of Phillip's loss is enormous but nothing compares to the loss felt by those closest to him.
"Phillip was a cherished son, brother, friend and team-mate. In these darkest of hours cricket puts its collective arms around the Hughes family."
Hughes, who was wearing a protective helmet, collapsed face first onto the pitch after being hit by a ball on the back, lower left side of his head from pace bowler Sean Abbott as he attempted a pull shot.
He was given mouth-to-mouth resuscitation and oxygen on the boundary line after being carried off the pitch on a stretcher.
He was taken to Sydney's St Vincent's Hospital, where he underwent surgery and was being monitored in the intensive care unit.
However, the governing body today confirmed the worst.
Sutherland continued: "'Hughesy, Huey or Hue-Dog - as he was known to many of his mates - was much-loved.
"You only have to sift through the thousands of messages of support, prayers and well wishes for Phillip from cricketers and supporters the world over to understand the affection felt towards him.
"He will forever be remembered as one of the elite few to have worn the Baggy Green cap - cap number 408, to be precise. He was a hero to kids around the nation, particularly those in the region around his home town of Macksville in New South Wales that he did so proud in his 26 Test matches - a tally that looked certain to grow, but now sadly never will.
"He will be sadly missed and forever remembered."
Australian team doctor Peter Brukner said: "He never regained consciousness following his injury. He was not in pain before he passed and was surrounded by his family and close friends."
Following the incident, the match between South Australia and New South Wales was called off for the day before being abandoned entirely, while the latest round of Sheffield Shield games has now followed suit.
Hughes' death will no doubt spark renewed debate about the headgear warn by batsmen, and also the composition of the balls being used.
The second day's play was suspended in the Test match between Pakistan and New Zealand in Sharjah as a mark of respect, with the contest now due to finish on Monday.
Hughes was well known to English fans both internationally and domestically after spells with Hampshire, Middlesex and Worcestershire, as well as playing in the Indian Premier League.
A 26-Test international, Hughes' last appearance for Australia came in a one-day international against Pakistan in October.
He memorably scored two hundreds in just his second Test match against South Africa, with his last five-day appearance coming against England at Lord's last summer.
In the Test prior to that he scored 81 at Trent Bridge alongside Ashton Agar in a last-wicket stand that nearly produced a memorable win.
Australia captain Michael Clarke, a close friend of Hughes, read out a statement on behalf of the Hughes family.
It read: "We're devastated by the loss of our much-loved son and brother Phillip.
"It's been a very difficult few days, we appreciate all the support we have received from family, friends, players, Cricket Australia and the general public.
"Cricket was Phillip's life and we as a family shared that love of the game with him. We would like to thank all the medical and nursing staff at St Vincent's Hospital and Cricket New South Wales medical staff for their great efforts with Phillip.
"We love you."
A clearly emotional Clarke then stood up and left the room.
An injury to Clarke had led to talk of Hughes getting a recall for the first Test against India, which is slated to begin next week in Brisbane but may now be in doubt of going ahead.
Phillip Hughes' Australia team-mates led the emotional tributes to the batsman following his death at the age of 25.
Hughes died on Thursday, two days after being struck on the head by a bouncer while batting for South Australia against New South Wales at the Sydney Cricket Ground.
An ashen-faced Australia captain Michael Clarke said in a statement on behalf of the Hughes family: "We're devastated by the loss of our much-loved son and brother Phillip. Cricket was Phillip's life, and we as a family shared that love of the game with him. We love you."
Clarke was one of a number of players who rushed to visit Hughes at St Vincent's Hospital where he was being treated, with the likes of David Warner pictured in tears as he left the hospital.
Australia batsman Steve Smith said on Twitter: "Rest in peace Hughesy. I am really going to miss you. You were 1 of the great blokes and I will never forget you. £408 will live on forever."
Hughes was the 408th man to play Test cricket for Australia.
Australia coach Darren Lehmann tweeted: "RIP you little champ, we are all going to miss you!"
Jason Gillespie, the Yorkshire coach and former Australia fast bowler, said on Twitter he was "shaking" at the news.